%0 Journal Article %T Molecular polymorphism, differentiation and introgression in the period gene between Lutzomyia intermedia and Lutzomyia whitmani %A Camila J Mazzoni %A Nataly A Souza %A Claudia Andrade-Coelho %A Charalambos P Kyriacou %A Alexandre A Peixoto %J BMC Evolutionary Biology %D 2006 %I BioMed Central %R 10.1186/1471-2148-6-85 %X We analyzed the molecular variation within the clock gene period (per) of these two species in five different localities in Eastern Brazil. AMOVA and Fst estimates showed no evidence for geographical differentiation within species. On the other hand, the values were highly significant for both analyses between species. The two species show no fixed differences and a higher number of shared polymorphisms compared to exclusive mutations. In addition, some haplotypes that are "typical" of one species were found in some individuals of the other species suggesting either the persistence of old polymorphisms or the occurrence of introgression. Two tests of gene flow, one based on linkage disequilibrium and a MCMC analysis based on coalescence, suggest that the two species might be exchanging alleles at the per locus.Introgression might be occurring between L. intermedia and L. whitmani in period, a gene controlling behavioral rhythms in Drosophila. This result raises the question of whether similar phenomena are occurring at other loci controlling important aspects of behavior and vectorial capacity.The Phlebotominae sand flies Lutzomyia intermedia Lutz & Neiva 1912 and Lutzomyia whitmani Antunes & Coutinho 1912 are vectors of cutaneous leishmaniasis in Brazil. These are closely related species that can be only distinguished by a few morphological differences [1] and both show high anthropophily and reported natural infections with Leishmania in different regions of Brazil [2].Despite their importance as vectors, only a handful of studies have been carried out in these two species using molecular techniques [3-6]. One of the most important findings from an epidemiological perspective is the evidence obtained for introgression between the two species using mitochondrial DNA [4]. This was particularly interesting because apparently, only lineages of L. whitmani sympatric with L. intermedia have been involved in cutaneous leishmaniasis transmission in the peridomestic enviro %U http://www.biomedcentral.com/1471-2148/6/85